Image forming method

Abstract

The improved image forming method reduces the chance of toner particles of adhering or filming on the surfaces of impression members, thereby enabling the formation of high-resolution image in a consistent and reliable manner. The method uses a charging member 4 for contact charging a latent image carrier 1, a developing member 11 for impression development of a pattern of latent electrostatic image, a transfer member 18 for impression transfer of the developed toner 10, and an impression cleaning member 23 for cleaning the latent image carrier 1 after toner transfer. The toner to be used satisfies one of the following conditions: that it should have an external additive added in an amount of 0.4 to 1.2 wt %; that it should have a volume resistivity of at least 1017 OMEGA cm; that it should incorporate a release agent in an amount no more than 5 wt %; or that it should not include large amounts of fine particles with a size of 5 mu m and less, or coarse particles with a size of 12.7 mu m and more.

What is claimed is: 
     
       1. An image forming method, comprising: charging a latent image carrier to a predetermined potential via a contact charging member;   exposing said latent image carrier to light to form a latent electrostatic image;   developing said latent electrostatic image by imparting a toner to said latent image to render it visible;   pressing an impression transfer member into contact with said latent image carrier to transfer developed toner to a recording medium, said toner being comprised of matrix resin particles having an external additive in an amount of 0.4 to 1.6 wt %; and   pressing a cleaning member into contact with said latent image carrier to remove toner remaining on said carrier after said transfer.   
     
     
       2. A method according to claim 1, wherein said developing step is performed by pressing said developing member into contact with said latent image carrier, and wherein said external additive in said toner is present in an amount of 0.4 to 1.2 wt %. 
     
     
       3. A method according to claim 1, wherein said external additive comprises hydrophobic silica having an average primary particle size of at least 10 nm. 
     
     
       4. A method according to claim 2, wherein said toner has a volume resistivity of at least 10 17  ohm-cm. 
     
     
       5. A method according to claim 2, wherein said toner includes a release agent in an amount ranging from 1 to 5 wt %. 
     
     
       6. A method according to claim 1, wherein said toner has a volume average particle size of 6 to 10 μm, with the percentage of toner particles not larger than 5 μm being no more than 15% of said toner particles, and the percentage of toner particles not smaller than 12.7 μm being no more than 5% of said toner particles. 
     
     
       7. An image forming method, comprising: charging a latent image carrier to a predetermined potential;   exposing said latent image carrier to light to form a latent electrostatic image;   developing said latent electrostatic image by pressing an impression developing member into contact with said latent image carrier to impart a toner to said latent image to render it visible; and   pressing an impression transfer member into contact with said latent image carrier to transfer developed toner to a recording medium, said toner having a volume resistivity of at least 10 17  ohm-cm.   
     
     
       8. A method according to claim 7, wherein said toner is comprised of matrix resin particles having a charge control agent additive in an amount ranging from 1 to 5 wt %. 
     
     
       9. A method according to claim 7, wherein said toner is comprised of matrix resin particles having a colorant additive in an amount ranging from 1 to 10 wt %. 
     
     
       10. A method according to claim 7, wherein said toner is comprised of matrix resin particles having a release agent additive in an amount ranging from 1 to 5 wt %. 
     
     
       11. A method according to claim 7, wherein said toner has a volume average particle size of 6 to 10 μm, with the percentage of toner particles not larger than 5 μm being no more than 15% of said toner particles, and the percentage of toner particles not smaller than 12.7 μm being no more than 5% of said toner particles. 
     
     
       12. An image forming method, comprising: charging a latent image carrier to a predetermined potential;   exposing said latent image carrier to light to form a latent electrostatic image;   developing said latent electrostatic image by pressing an impression developing member into contact with said latent image carrier to impart a toner to said latent image to render it visible; and   transferring developed toner to a recording medium; and   pressing a cleaning member into contact with said latent image carrier to remove toner remaining on said carrier after said transfer, wherein said toner is comprised of matrix resin particles having a release agent additive in an amount ranging from 1 to 5 wt %.   
     
     
       13. A method according to claim 12, wherein said toner has a volume average particle size of 6 to 10 μm, with the percentage of toner particles not larger than 5 μm being no more than 15% of said toner particles, and the percentage of toner particles not smaller than 12.7 μm being no more than 5% of said toner particles. 
     
     
       14. An image forming method, comprising: contacting a charging member to a latent image carrier to charge the latent image carrier to a predetermined potential;   exposing said latent image carrier to light to form a latent electrostatic image;   developing said latent electrostatic image by pressing a developing member into contact with said latent image carrier to impart a toner to said latent image to render it visible;   pressing an impression transfer member into contact with said latent image carrier to transfer developed toner to a recording medium; and   pressing a cleaning member into contact with said latent image carrier to remove toner remaining on said carrier after said transfer, wherein said toner has a volume average particle size of 6 to 10 μm, with the percentage of toner particles not larger than 5 μm being no more than 15% of said toner particles, and the percentage of toner particles not smaller than 12.7 μm being no more than 5% of said toner particles.